[MIPS] PCI: Make dev pointer argument of pcibios_map_irq const.

This is to break the code of people who think they are supposed to scribble
into the pci device structure - it's off limits.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/pci/fixup-yosemite.c b/arch/mips/pci/fixup-yosemite.c
index 81d77a5..fdafb13 100644
--- a/arch/mips/pci/fixup-yosemite.c
+++ b/arch/mips/pci/fixup-yosemite.c
@@ -26,7 +26,7 @@
 #include <linux/init.h>
 #include <linux/pci.h>
 
-int __init pcibios_map_irq(struct pci_dev *dev, u8 slot, u8 pin)
+int __init pcibios_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
 {
 	if (pin == 0)
 		return -1;